Rinsho Shinkeigaku (Clinical Neurology)

Brief Clinical Note

A case of middle-aged onset sialidosis type I

Yuka Sakazume, M.D.1), Makoto Tanaka, M.D.1), Itsuo Isobe, M.D.2), Rika Tominaga, B.S.3), Eiji Nanba, M.D.3), and Koichi Okamoto, M.D.1)

1)Department of Neurology, Gunma University Graduate School of Medicine
2)Isobe Clinic
3)Division of Functional Genomics, Reserch Center for Bioscience and Technology, Tottori University

We reported a patient with middle-aged onset sialidosis type I. A 52-year-old Japanese man was referred to our hospital because of dysarthria, involuntary movement of his extremities and gait disturbance since the age of 46 years. On admission, neurological examination revealed scanning speech, action myoclonus, cerebellar ataxia and cherry-red spots. Vacuolated lymphocytes were found in peripheral blood. Brain 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET) showed decreased glucose metabolism in the cerebellum. Enzymological analysis using his skin fibroblasts revealed primary deficiency of sialidase activity. Sialidase gene analysis identified compound heterozygotes for base substitusions of 239T-to-C and 649G-to-A, which resulted in amino acid alterations of P80L and V217M, respectively. These mutations have been reported in Japanese sialidosis type II (P80L) and I (V217M). Further studies are required to reveal effects of gene mutations on residual enzyme activities and phenotypes.

(CLINICA NEUROL, 44: 541|544, 2004)
key words: sialidosis type I, PET, sialidase gene mutaition, compound heterozygote

(Received: 3-Sep-03)